Installation Guide

because the galvanized zinc coating is ineffective once it has been over-
heated.
11. Operating the stove, heater or fireplace when the connector is red hot
is very dangerous. This indicates overfiring or a chimney fire. Stop firing,
close the dampers, let things cool off, and keep watching for problems on
nearby walls and furnishings.
12. The slope of the horizontal portion of a connector of 1/4 inch per foot is
sometimes a building code requirement. This slope will have little effect on
safety or appliance operation. If the connector is vertical, it should be
installed with the crimped end down. If it can be sloped between the stove
and chimney, use 45 degree one piece leakproof elbows (such as the
corrugated type), and try to maintain sufficient slope so that any conden-
sate liquid runs back toward the appliance. To keep liquids from coming out
connector joints, the small (or crimped) end should always be down - or
toward the stove or fireplace.
CLEARANCES FOR METALBEST CHIMNEY SYSTEM INSULATED
PIPE
Such parts as Fire Stops and ceiling supports are intended to be attached
directly to the framing or to ceiling, or floors. These auxiliaries, which are in
contact with wood or other combustibles, are designed and tested to
assure that they do not overheat at points of contact.
The instruction sheets for individual parts and the table on the back page
give proper framing dimensions, which in turn define the proper clearance.
Wherever these instructions illustrate the use of a required spacer or fire
stop, the purpose of the part is to maintain and assure the proper clear-
ance.
Remember that the most important clearance requirement is that it must be
AIR SPACE.
ENCLOSURE: Interior or exterior residential chimneys should be enclosed
where they extend through closets, storage areas, or habitable spaces
where the surface of the chimney could be contacted by persons or
combustible materials. The space between the enclosure and chimney
should be at least the required 2" minimum airspace clearance to combus-
tibles. (SEE SHEET S-2 FOR PROPER USE OF FIRESTOPS IN AN ENCLO-
SURE). Enclosures may be built of ordinary drywall or plywood at the
required minimum of 2 INCHES AIR SPACE CLEARANCE. While properly
installed firestops or supports help maintain the necessary clearances to
combustibles at ceilings or joist areas, there are no special parts to maintain
clearance to inside surfaces of walls or enclosures; therefore, the builder
and the chimney installer should take all necessary precautions to assure
that this 2 inch minimum clearance or more is maintained.
In unoccupied attics, it is very important to be sure that blown-in or other
insulation does not come in contact with the chimney. A full enclosure built
in the attic should extend to the roof; however, it need only be finished well
enough to keep insulation and stored furnishings away from the chimney.
If a full enclosure is not built, an Attic Insulation Shield (AIS) MUST be used.
See Fig. 6.
A chimney enclosure is also highly recommended for any outdoor, exterior-
mounted chimney located outside of the building wall. This enclosure can
be helpful in reducing internal condensation, creosote build-up and metal
deterioration. Also the enclosure, by protecting the chimney from cold
outdoor temperatures, may improve draft and appliance operation.
At the upper end of this outdoor enclosure, the chimney should be flashed
with the flashing/storm collar termination shown in Sheet S-3.
If the enclosure is exterior, without penetration of the building enclosure,
wall bands should be used to provide the necessary lateral stability.
Regardless of the benefits of the exterior enclosure, better chimney and
appliance operation will be obtained if the chimney is located entirely inside
the heated part of the building (except of course for the part above the
roof).
Enclosures of ordinary wood framing with gypsum drywall or plywood
walls may be built only in one and two-family dwellings. For other types of
buildings, multiple occupancies or high rise construction, additional fire
resistance is required for enclosures as follows:
A factory-built chimney that extends through any zone above that on which
the connected appliance is located is to be provided with an enclosure
having a fire resistance rating equal to or greater than that of the floor or
roof assemblies through which it passes.
Even with a fire resistance rated enclosure, the use of Fire Stops at
every floor level is recommended to stabilize the chimney and to retard
possible fire spread external to the chimney.
FIRESTOPPING
(See Also Sheet S-2)
A fire stop is any part of the building structure which prevents the spread
of a fire or circulation of air. Where a MetalBest Chimney System is
enclosed and framed at 2" clearance, a Firestop/Joist Shield (JS) or Fire
Stop/Wall Spacer (WS) is the proper firestop to use at every floor. Part “JS”
may be used with all MetalBest Chimney System models. Part “WS” may
be used only with Model SSII.
If the enclosure or space around the chimney is larger than usual, or
irregular in shape, attach galvanized metal plates 28 gauge or heavier all
around the edges of the Fire Stop/Joist Shield (JS) or Firestop/Wall Spacer
(WS) as necessary. These should be wide enough so that when installed,
the gap is closed to vertical air circulation around the chimney and the pipe
is securely spaced and centered.
For firestopping to be fully effective, all ceiling and floor penetrations should
be fully framed and closed on all four vertical sides. This framing helps
delay horizontal spread of fire and controls unnecessary horizontal air
leakage through intermediate floors.
CHIMNEY JOINT SECURITY
All MetalBest chimney joints must be reinforced with either of 2 choices:
1. Locking Bands (LB). These are furnished with pipe and elbows.
or
2. Stainless steel sheet metal screws (3 minimum) per joint, these are an
optional extra.
The stainless steel sheet metal screws, size #8 x 1/2" must be evenly
spaced around the joint and 1/2 inch above the joint separation. Before
installing either the screws or the Locking Band, the joint should be
All insulated MetalBest Chimney Systems' gas-carrying chim-
ney parts are marked with important safety information con-
firming minimum airspace clearance to combustibles. This mini-
mum airspace clearance to combustibles is important in order
to keep combustible materials from overheating and creating a
fire hazard. Never fill required airspace with insulation or even
non-combustible material, since such actions could cause over-
heating. If you are uncertain about a particular installation, con-
tact Selkirk at the number referenced at the end of these in-
structions.
Attic
Attic Insulation
Shield (AIS)
Nail Flanges
To Framing
Maximum
Insulation
Height 10”
Above Framing
Fire Stop/ Joist Shield (JS)
MetalBest
Chimney
Section
FIG. 6 FIRE STOP/ JOIST SHIELD (JS) USED
WITH ATTIC INSULATION SHIELD